1. Field of the Invention
The present invention relates to a channel frequency storing method for a vehicle radio, and more specifically to a channel storing method for a vehicle radio which can facilitate listening to radio broadcasting and traffic information in plural broadcasting areas, when the vehicle is travelling from one broadcasting area to another broadcasting area.
2. Description of the Prior Art
In general, there are plural broadcasting areas in any one country (e.g. there are ten major broadcasting areas in Japan). Further, there are a few or several broadcasting stations (i.e. channels) in one broadcasting area, and further the frequencies of these plural channels are different from each other in one area and further are different in plural areas from each other.
In the conventional vehicle radio, in general a plurality of channel frequencies in only a single broadcasting area are previously selected and stored in a memory, so that any desired radio broadcasting channel can be received by simply depressing a key (one-touch station selection), as disclosed in "Service Weekly" by NISSAN Corp. No. 656, Jun. 1989, E-46 to 50.
In the prior-art vehicle radio as described above, however, since the number and the area of broadcasting channels which can be previously selected are limited (e.g. 6 AM stations and 6 FM stations in one broadcasting area), there exists a problem in that it is impossible to hear radio broadcasts or traffic information in a vehicle when travelling through different broadcasting areas by such a one-touch station selection method.
In more detail, whenever the vehicle travels from one broadcasting area to another broadcasting area, the driver must newly select channels whose radio wave field intensities exceed a predetermined level by manual tuning or automatic tuning and then store these selected channels again in the preset memory. Further, in the case of SAM (station automemory method), previously selected channels are once erased and then newly selected channels are overwritten again in the preset memory, thus resulting in a problem in that it takes a great deal of time to select and preset new broadcasting stations or channel frequencies whenever the vehicle enters a new broadcasting area.